1. Field of the Invention
The present invention relates to a particulate matter accumulation amount detection apparatus and method configured and arranged to estimate an amount of particulates accumulated in an exhaust gas purification filter that is configured and arranged to trap the particulates that are contained in exhaust gas discharged from an engine to prevent the particulates from being discharged to the atmosphere.
2. Background Information
Japanese Laid-Open Patent Application Publication No. 2002-97930 discloses a conventional exhaust gas purification device for a diesel engine in which a diesel particulate filter (hereinafter referred as “DPF”) is installed in an exhaust passage of the diesel engine. The DPF is configured and arranged to purify exhaust gas discharged from the diesel engine by trapping particulate matter (hereinafter referred as “PM”) in the exhaust gas. As the DPF continues to trap PM, the DPF eventually becomes clogged. Accordingly, the conventional exhaust gas purification device is configured to regenerate the DPF by raising the temperature of the exhaust gas to forcibly burn off, and thus, eliminate the accumulated PM in the DPF when it is determined that PM has accumulated in the DPF over a certain level.
The conventional exhaust gas purification device as disclosed in the above mentioned reference is configured to determine whether PM has accumulated in the DFP to an extent that necessitates the regeneration of the DPF based on a differential pressure (upstream-downstream differential pressure) between inlet and outlet of the DPF.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved particulate matter accumulation amount detection apparatus and method. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.